/*      $OpenBSD: tmpfs_mem.c,v 1.11 2025/11/21 09:49:33 mvs Exp $      */
/*      $NetBSD: tmpfs_mem.c,v 1.4 2011/05/24 01:09:47 rmind Exp $      */

/*
 * Copyright (c) 2010, 2011 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Mindaugas Rasiukevicius.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

/*
 * tmpfs memory allocation routines.
 * Implements memory usage accounting and limiting.
 */

#include <sys/param.h>
#include <sys/namei.h>
#include <sys/pool.h>
#include <sys/vnode.h>
#include <sys/malloc.h>

#include <tmpfs/tmpfs.h>

extern struct pool      tmpfs_dirent_pool;
extern struct pool      tmpfs_node_pool;

uint64_t tmpfs_bytes_limit;
uint64_t tmpfs_bytes_used = 0;

void
tmpfs_mntmem_init(struct tmpfs_mount *mp, uint64_t memlimit)
{

        rw_init(&mp->tm_acc_lock, "tacclk");
        mp->tm_mem_limit = memlimit;
        mp->tm_bytes_used = 0;
}

void
tmpfs_mntmem_destroy(struct tmpfs_mount *mp)
{

        KASSERT(mp->tm_bytes_used == 0);
        /* mutex_destroy(&mp->tm_acc_lock); */
}

uint64_t
tmpfs_pages_total(struct tmpfs_mount *mp)
{
        uint64_t total;

        if (mp->tm_mem_limit)
                total = mp->tm_mem_limit;
        else {
                total = tmpfs_bytes_limit - tmpfs_bytes_used +
                    mp->tm_bytes_used;
        }

        return (total >> PAGE_SHIFT);
}

uint64_t
tmpfs_pages_avail(struct tmpfs_mount *mp)
{
        uint64_t free;

        rw_assert_anylock(&mp->tm_acc_lock);

        if (mp->tm_mem_limit)
                free = mp->tm_mem_limit - mp->tm_bytes_used;
        else
                free = tmpfs_bytes_limit - tmpfs_bytes_used;

        return (free >> PAGE_SHIFT);
}

int
tmpfs_mem_incr(struct tmpfs_mount *mp, size_t sz)
{
        int ret = 0;

        rw_enter_write(&mp->tm_acc_lock);

        if (mp->tm_mem_limit) {
                if ((mp->tm_mem_limit - mp->tm_bytes_used) < sz)
                        goto out;
        } else {
                if ((tmpfs_bytes_limit - tmpfs_bytes_used) < sz)
                        goto out;
                tmpfs_bytes_used += sz;
        }

        mp->tm_bytes_used += sz;

        ret = 1;
out:
        rw_exit_write(&mp->tm_acc_lock);

        return ret;
}

void
tmpfs_mem_decr(struct tmpfs_mount *mp, size_t sz)
{
        rw_enter_write(&mp->tm_acc_lock);
        KASSERT(mp->tm_bytes_used >= sz);
        if (mp->tm_mem_limit == 0)
                tmpfs_bytes_used -= sz;
        mp->tm_bytes_used -= sz;
        rw_exit_write(&mp->tm_acc_lock);
}

struct tmpfs_dirent *
tmpfs_dirent_get(struct tmpfs_mount *mp)
{

        if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_dirent))) {
                return NULL;
        }
        return pool_get(&tmpfs_dirent_pool, PR_ZERO|PR_WAITOK);
}

void
tmpfs_dirent_put(struct tmpfs_mount *mp, struct tmpfs_dirent *de)
{

        tmpfs_mem_decr(mp, sizeof(struct tmpfs_dirent));
        pool_put(&tmpfs_dirent_pool, de);
}

struct tmpfs_node *
tmpfs_node_get(struct tmpfs_mount *mp)
{

        mp->tm_nodes_cnt++;
        if (mp->tm_nodes_cnt > mp->tm_nodes_max) {
                mp->tm_nodes_cnt--;
                return NULL;
        }
        if (!tmpfs_mem_incr(mp, sizeof(struct tmpfs_node))) {
                mp->tm_nodes_cnt--;
                return NULL;
        }
        return pool_get(&tmpfs_node_pool, PR_WAITOK);
}

void
tmpfs_node_put(struct tmpfs_mount *mp, struct tmpfs_node *tn)
{

        mp->tm_nodes_cnt--;
        tmpfs_mem_decr(mp, sizeof(struct tmpfs_node));
        pool_put(&tmpfs_node_pool, tn);
}

/*
 * Quantum size to round-up the tmpfs names in order to reduce re-allocations.
 */

#define TMPFS_NAME_QUANTUM      (32)
#define roundup2(x, y)  (((x)+((y)-1))&(~((y)-1))) /* if y is powers of two */

char *
tmpfs_strname_alloc(struct tmpfs_mount *mp, size_t len)
{
        const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM);

        KASSERT(sz > 0 && sz <= 1024);
        if (!tmpfs_mem_incr(mp, sz)) {
                return NULL;
        }
        return malloc(sz, M_TEMP, M_WAITOK); /* XXX */
}

void
tmpfs_strname_free(struct tmpfs_mount *mp, char *str, size_t len)
{
        const size_t sz = roundup2(len, TMPFS_NAME_QUANTUM);

        KASSERT(sz > 0 && sz <= 1024);
        tmpfs_mem_decr(mp, sz);
        free(str, M_TEMP, sz);
}

int
tmpfs_strname_neqlen(struct componentname *fcnp, struct componentname *tcnp)
{
        const size_t fln = roundup2(fcnp->cn_namelen, TMPFS_NAME_QUANTUM);
        const size_t tln = roundup2(tcnp->cn_namelen, TMPFS_NAME_QUANTUM);

        return (fln != tln) || memcmp(fcnp->cn_nameptr, tcnp->cn_nameptr, fln);
}